Field of the Invention
The present invention relates to a conductivity inspection method of a printed circuit board, and a manufacturing method of the printed circuit board.
Description of Related Art
Actuators are used in drive devices such as hard disc drive devices. Such an actuator includes an arm provided rotatably around a rotation shaft, and a suspension board with a circuit for a magnetic head that is attached to the arm. The suspension board with a circuit is a printed circuit board for positioning the magnetic head at a desired track of a magnetic disc.
In a printed circuit board in JP 2010-135754 A, first to fourth electrode pads are formed on one surface of an insulating layer. The first electrode pad and the second electrode pad are electrically connected by a first wiring trace, and the third electrode pad and the fourth electrode pad are electrically connected by a second wiring trace.
In the first wiring trace, a first line connected to the first electrode pad branches into second and third lines. The second and third lines join as a fourth line, and the fourth line is connected to the second electrode pad. In the second wiring trace, a fifth line connected to the third electrode pad branches into sixth and seventh lines. The sixth and seventh lines join as an eighth line, and the eighth line is connected to the fourth electrode pad.
Here, the second, sixth, third and seventh lines are arranged to line up in this order. A portion of the third line intersecting with the sixth line is arranged on the other surface of the insulating layer in order to avoid interference of the third line with the sixth line. The portion of the third line arranged on the other surface of the insulating layer is electrically connected to the third line arranged on the one surface of the insulating layer through a pair of first vias. Similarly, a portion of the sixth line intersecting with the third line is arranged on the other surface of the insulating layer. The portion of the sixth line arranged on the other surface of the insulating layer is electrically connected to the sixth line arranged on the one surface of the insulating layer through a pair of second vias.